I've seen a couple references to a reverse flow under gravel filter, but I don't recall ever seeing one at the store. 
What is a reverse ugr?
- Thread starter Dragon Queen
- Start date
It's a regular UGF, just set the powerheads to reverse flow.
EDIT: Should have mentioned the mechanical filtration as well. It looks to be one of those days...
EDIT: Should have mentioned the mechanical filtration as well. It looks to be one of those days...
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Like Harlock said. Just be sure to get powerheads that can be set to reverse (i.e. you want to push the water down into the plate rather that pull it up) and put a foam prefilter on the powerhead so you are not putting debris into the filter.
Most people feel it better for a number of reasons. It keeps piles of fishy poo from collecting under a UGF plate (most people do not know how to properly clean a UGF), it is easier to maintain and it has the bonus if the mechanical filtration of the prefilter. If your powerhead doesn't have a reverse on it then you obviously have to buy a new powerhead if you want to run a RF-UGF.
A RFUGF is better for biological filtration because the chances of disturbing the bacteria on the bottom of the gravel are less, as opposed to a regular UGF, which has bacteria mostly on the top of the gravel. A RFUGF also forces much more water through the UGF plate than a lift tube will(air powered), as well as keeping decaying matter out of the gravel.
If your power head doesn't have reverse? No problem!
Get one of These
If your power head doesn't have reverse? No problem!
Get one of These
A RFUGF is better for biological filtration because the chances of disturbing the bacteria on the bottom of the gravel are less, as opposed to a regular UGF, which has bacteria mostly on the top of the gravel.
Wrong. In a UGF, the water is forced through all of the gravel, and the bacteria are fairly well distributed throughout the entire bed. With RUGF, there is little to no difference, other than which direction the water is traveling.
A RFUGF also forces much more water through the UGF plate than a lift tube will(air powered), as well as keeping decaying matter out of the gravel.
Partially correct--but it will depend on how it's setup. Powerheads can be used for either direction flow, but are actually slower in reverse operation. Without a prefilter, RUGF will still traop solid wastes in the gravel bed and result in more decaying matter.
Wrong. In a UGF, the water is forced through all of the gravel, and the bacteria are fairly well distributed throughout the entire bed. With RUGF, there is little to no difference, other than which direction the water is traveling.
A RFUGF also forces much more water through the UGF plate than a lift tube will(air powered), as well as keeping decaying matter out of the gravel.
Partially correct--but it will depend on how it's setup. Powerheads can be used for either direction flow, but are actually slower in reverse operation. Without a prefilter, RUGF will still traop solid wastes in the gravel bed and result in more decaying matter.
What does it do to plants in the gravel, most of mine are stems I shove into my gravel.
Also, I have a air pump on the other side that goes through my carbon filter, what kind of havoc would that do to have a powerhead on reverse on one side and a carbon air filter as a normal ugf on the other?
Also, I have a air pump on the other side that goes through my carbon filter, what kind of havoc would that do to have a powerhead on reverse on one side and a carbon air filter as a normal ugf on the other?
Duh.....Stupid me 
I guess it makes sence that the bacteria will be where the water flows....
The kit that I listed for a RUGF has a sponge pre-filter, so that would make it better than a UGF, correct?
I guess it makes sence that the bacteria will be where the water flows....
The kit that I listed for a RUGF has a sponge pre-filter, so that would make it better than a UGF, correct?
Yes, having the prefilter is a big improvement since it prevents solid wastes from getting into the gravel bed.
The jury is still out on how any kind of UGF impacts plants. There is some evidence that both can be compromised by the build up of roots in the gravel, impeding water flow through these areas. And, of course, with a UGF, cleaning the substrate is required, and with plants, this can be complicated since you don't want to remove all the nutrients from the plants, nor disturb the root bed with deep cleaning. There is some concern that the constant flow of oxygenated water of the roots may also compromise the plant growth, as well, and there are a some people testing the setups.
You will want to use equivalent setups for bringing the water in. This promotes equal water flow, and discourages 'slow' spots, where the gravel could compact, reducing efficiency. You do not want one side running reverse and the other running 'normal', as this will allow the 'normal' side to build up solid wastes. Running carbon is generally not needed for most setups, so removing it entirely from the system should not have any negative impact on the system. If you are converting from a UGF, you must clean the gravel bed very, very well, or the accumulated debris will be pushed into the water column, creating ideal conditions for a bacterial bloom and cloudy water.
The jury is still out on how any kind of UGF impacts plants. There is some evidence that both can be compromised by the build up of roots in the gravel, impeding water flow through these areas. And, of course, with a UGF, cleaning the substrate is required, and with plants, this can be complicated since you don't want to remove all the nutrients from the plants, nor disturb the root bed with deep cleaning. There is some concern that the constant flow of oxygenated water of the roots may also compromise the plant growth, as well, and there are a some people testing the setups.
You will want to use equivalent setups for bringing the water in. This promotes equal water flow, and discourages 'slow' spots, where the gravel could compact, reducing efficiency. You do not want one side running reverse and the other running 'normal', as this will allow the 'normal' side to build up solid wastes. Running carbon is generally not needed for most setups, so removing it entirely from the system should not have any negative impact on the system. If you are converting from a UGF, you must clean the gravel bed very, very well, or the accumulated debris will be pushed into the water column, creating ideal conditions for a bacterial bloom and cloudy water.